Treatment for Childhood Absence Epilepsy (CAE) is largely empiric. Although there are three efficacious antiepileptic drugs (AEDs) - ethosuximide (ETX), lamotrigine (LTG), valproic acid (VPA) - each has variable success in seizure control, as well as treatment-limiting toxicities. This project is being resubmitted as two linked R01 applications. The clinical proposal, "Childhood Absence Epilepsy - Rx, PK/PK, Genetics," (PI: T. Glauser, Co-PI: P. Adamson) is being resubmitted by the Cincinnati Children's Hospital. The objectives of the clinical trial are twofold: a) identify the optimal initial AED in terms of seizure control and lowest toxicity incidence; and b) to determine the clinical, pharmacokinetic and pharmacogenetic factors underlying the inter-individual variation in AED response and toxicity. This linked R01 proposal will establish the Childhood Absence Epilepsy Coordinating Center [CHAECC] at The Children's Hospital of Philadelphia to support this broad, integrated plan to study CAE. A strong and efficient coordinating center is needed in a project of this magnitude and complexity to ensure that the scientific goals are achieved in a timely manner and to a high standard of scientific excellence and data integrity as well as subject safety. The Children's Hospital of Philadelphia (CHOP) has established a highly experienced team to provide this coordinating center function. The aims of the CHAECC are to provide: 1) operational support to implement the protocol; 2) data base and data management for the protocol and the Core's data; 3) biostatistical analyses of the project aims. To meet these goals, the CHAECC will perform start-up activities to implement the project, coordinate all communication activities, oversee adherence to Good Clinical Practice and HIPPA guidelines in protocol implementation, and will work closely with the Scientific Leadership of the study. The CHAECC will develop procedures for data collection, transference, and storage in a secure relational database. The CHAECC will coordinate receipt of video EEG's by Core readers and meetings to achieve consensus in interpretations. It will conduct all statistical analyses and support preparation of reports, manuscripts and presentations.